Protecting RFID security and privacy is very important to the future development of RFID technology. In addition, the low-cost budget of RFID tags imposes a significant challenge to the design and implementation of privacy preserving RFID protocols. Therefore, in this thesis low-cost cryptographic based privacy preserving authentication protocols for RFID devices are examined. Since privacy models are used to formalise adversary capability and to evaluate whether an RFID protocol preserves privacy or not, the first extensive survey of privacy models for RFID authentication protocols is presented. Based on a comprehensive study of the important properties of RFID systems, namely privacy, scalability and low hardware cost, a range of novel RFID security protocols have been proposed. Since the LPN problem can be used as a hardware friendly cryptographic primitive, a low-cost forward private authentication protocol utilising the LPN problem is presented. A practical RFID protocol needs to be scalable, and the scalability performance is determined by both the RFID tags and reader. Therefore, novel techniques for balancing the performance between scalability and forward privacy are proposed, which can be used to reduce the hardware cost on the tag and the storage cost on the server, and also to accelerate the tag look-up procedure on the server. In addition, since asymmetric-key cryptography can be used to offer perfect constant-time scalability and ID based cryptography can be used to reduce the key management cost on the server, novel privacy-preserving protocols and a low-cost hardware architecture , based on an existing ID-based asymmetric-key NIKD scheme, are proposed for RFID-based health care applications.

Location estimation performance is not always satisfactory and improving it can be expensive. The performance of location estimation technology can be increased by refining the existing location estimation technologies. A better way of increasing performance is to use multiple technologies and combine the available data provided by them in order to obtain better results. Also, maintaining one's location privacy while using location estimation technology is a challenge. How can this problem be solved? In order to make it easier to perform sensor fusion on the available data and to speed up development, a flexible framework centered around a component-based architecture was designed. In order to test the performance of location estimation using the proposed sensor fusion framework, the framework and all the necessary components were implemented and tested. In order to solve the location estimation privacy issues, a comprehensive design that considers all aspects of the problem, from the physical aspects of using radio transmissions to communicating and using location data, is proposed. The experimental results of testing the location estimation sensor fusion framework show that by using sensor fusion, the availability of location estimation is always increased and the accuracy is always increased on average. The experimental results also allow the profiling of the sensor fusion framework's time and energy consumption. In the case of time consumption, there is a 0.32% - 17.06% - 5.05% - 77.58% split between results overhead, engine overhead, component communication time and component execution time on an average. The more measurements are gathered by the data gathering components, the more the component execution time increases relative to all the other execution times because component execution time is the only one that increases while the others remain constant.

Most people are familiar with Radio Frequency Identification (RFID) technology as its applications are around us in many systems, such as anti-theft devices in shops, supermarkets and libraries, building access systems. The number of applications and devices has developed explosively in the past decade and has become one of the fastest growing sectors of the radio technology industry. RFID systems allow information to be attached to items such as products, animals or even people. This information may be read, and in some cases changed, by an RFID reader some distance away. RFID localisation systems are an active area of research as they add further capabilities to current RFID systems. Localisation allows the position of tagged items to be determined from the RFID communications signal. Current systems can confirm that a specific item is within the reader read range but finding the item requires a systematic search. The primary objective of this thesis is to build a new, economical and versatile 2.45 GHz localisation system for active and passive RFID tags. Alternative systems rely upon signal strength measurements and yield large uncertainties due to the unknown orientation of the tags. The proposed system reader consists of a microstrip switched beam array antenna. The array antenna allows the estimation of the angular position of the tag. The use of two or more readers provides the tags position by triangulation. The array antenna provides other advantages such as improved read range and mitigation against interference and multipath fading. In the process of designing the antenna array, several new, compact, slotted, circularly polarised, square patch antennas have been produced. A range of technologies have been applied to achieve miniaturisation of the microwave circuit elements require to drive the antenna array, the Butler matrix (BM). Fabricated circuits achieve significant size area reduction with similar performances compared to the conventional ones. These developments will have wide application beyond the RFID localisation system. Finally, accuracy of the system varies with angle due to the complicated relationships between Angle of Arrival (AoA) and port output powers. The localisation algorithm along with measured power inside the standard anechoic room show that the standard deviations of the AoA estimation errors less than 1.6° for most angles in the operational range from -90 degrees to 90 degree and a standard error less than 0.6o for AoA angles with 20o of the perpendicular at AoA with power ratios perturbed by additive noise of standard deviation 0.5 dB.

This dissertation deals with the challenge of power utility in South Africa which is on proactive detection of fallen power line conductors and real time sagging measurement together with slipping of such conductors. Various methods which are currently used for sag detection were characterized and evaluated to the aim of the research. A mathematical reconstruction done to estimate the lowest point of the conductor in a span is presented. Practical simulations and application of radio frequency identification (RFID) for sag detection is attempted through matlab software. RFID radar system is then analyzed in different modes and found to give precision measurement for sag in real time as opposed to global positioning system (GPS) if one dimension of the tag assumed fixed on the power line. Lastly errors detected on the measurements are corrected using a trainable artificial neural network. A conclusion is made by making recommendations in the advancement of the research. / Electrical Engineering / M. Tech. (Electrical Engineering)